12 pounds!
What kind of pound?
Avoirdupois pounds contain 7,000 grains..
Troy pounds contain 5,760 grains.
A troy ounce equals 480 grains.
Typical US silver coinage was struck @ $1.29/oz troy silver, and is 90% silver, 10% copper.
Assuming you have 12 pounds Av., you have 175 troy ounces of silver coins, which, @ 90% silver, contain 157.5 ounces of pure silver.
Silver, on today's market, is worth $13.59/ troy ounce.
Your coins are worth, in scrap value, $2,140. It is unlikely you could sell them for that price, but you should be able to get close.
The offer of $416.00 is nothing short of an insult.. Do NOT do business with such people. If they're smart enough to know to buy them, they're smart enough to know their true value.
Harold